Tool · UV exposure timer
The exposure timer built for the workshop, hands busy.
Drag the dial to set the time, haptic and audio feedback (one click per minute), a progress ring visible from across the room, several simultaneous timers for successive passes. Available on the Web — and linked to your UV panel via Bluetooth control.
What the timer does
A countdown designed for the darkroom.
01 · Drag-to-set dial
Drag the dial to set the minutes without typing a number. Ergonomics for wet or gloved fingers — no keyboard required.
02 · Haptic & audio feedback
One click per elapsed minute. End of exposure signalled by a long vibration and a distinct sound — you hear it even with your back turned.
03 · Progress ring
An SVG arc visible from two metres shows the percentage of time elapsed. A glance is enough, without approaching the screen.
04 · Parallel timers
Run several countdowns at once — pass 1, pass 2, development bath. Each timer runs independently, with its own ring.
Availability
The timer is available on the Web (free, sign-up required, 100 MB) and in the iOS app (Pro €9.90/month or Luminograph 1 year). Curve export as .acv only.
Linked to your UV panel
Automatic LED on and off.
The timer alone counts the time — you turn the UV source on and off. To go further, Calibration Flow’s Bluetooth UV control drives the LED panel directly: automatic start and stop at the end of the countdown, with no manual intervention.
This synchronisation requires a compatible controller connected to your panel, plus the native iOS app or Chrome desktop (Web Bluetooth). It is not available on other mobile browsers.
The result: you place the negative, you start, you step away. The panel switches off on its own — zero over-exposure, zero handling in the darkroom under white light.
Documentation
Manual & resources
- Manual · Harmonic timer — Calibration Flow — advanced use, pass sequences, harmonic calibration
- Bluetooth UV control — automatic LED panel control
- Manual · Calibration Flow tools — histogram, loupe, Smart Analyzer, UV calculator
- UV exposure time calculator — estimate the time before launching the timer
A calmer workshop, a more precise exposure.
Timer, UV calculator, 21-step chart, .acv curves — free on the Web with sign-up, Pro at €9.90/month or Luminograph 1 year.